Method for removing ink from printed paper



A. SCHREIBER, residin County, Ilhnols, have invented a certam' PAENT OFFLCE- HAROLD a. EYBICH, or PHOENIXYILLE, rnmrsrnvama, AND JOHN a. SC-HBEIBER,

OF CHICAGO, ILLINOIS, ASS IGNORS '10 TH E'PAPER DE-INKING 60., 0F CEIGAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

METHOD IGR REMOVING INK FROM PRIlVTED PAPER.

Be it known that we, HAROLD R. EYRICH, and JOHN A. Sonnnrenn, citizens of the United States, HAROLD R.- EYRICH residing at Phoenixville, Pennsylvania, and JOHN g at Chicago, Cook new and useful Improvement in Methods for Removin Ink from Printed Paper, of which the fol owing is' a specification.

This invention relates to the art of deinking print-paper and has for its object to provide a method whereby the ink may be expeditiously and economically removed from the paper, to the end that such paper maybe used as paper stock to produce 'a cleanwhite print-paper of good quality or given any suitable or desired color.

It has heretofore been proposed to deink paper by treating printed paper pulp with bleaching agencies in connection with collodial substances, such as silicic acid, silicates and alumina compounds. It has also been proposed to subject the paper to the action of chemicals which produce a soap, such as soda, margaric acid, and oleic acid, together with an absorbent earthy matter. Another method has been to subject the macerated or pulped paper stock containing the ink to theaction of an alkali in solu tion, together with a silicate of aluminum such as fullers earth, kaolin or other clays, silicate of magnesium such as talc, soapstone, etc., and then washing the fiber.

All of these methods have proved unsatisfactory or ineficient in the practical art, not only bec'ause'they did not thoroughly remove the ink but because the amount of materials necessarily employed and the extent of time required by the process rendered the cost so high that there was no economy in recovering the old stock as against the use of new stock. By the process hereinafter described, we are enabled to ex editiously and thoroughly remove the ink om the printed paper stock and produce a thoroughly satisfactory white printpaper therefrom, superior to any paperheretofore made from rint-paper stock and at a cost materially Below that of paper made from new stock, and thus efi'ect a saving not only in the price of the paper reproduced therefrom but also eflect economy in the consumption of the raw materials that Specification of Letters Patent.

7 Patented June 27, 1922.

Application filed April 27, 1921. Serial No. 465,026.

would be re uired if all new paper stock was employed. y

We have discovered that, if printed paper pulp is treated with an alkali tov decompose or break up the ink and then is subjected to a colloidal solution of the substance known as bentonite (of which there are a number of varieties), and then thoroughly washed, preferably in running water, the ink is thoroughly and expeditiously removed and the pulp left in a most excellent condition for the manufacture of a good grade of print-paper.

The inventive idea involved is capable of some variations and modifications without departing from the essential spirit, of the invention and, for the purpose of illustrating the invention, we herein describe one beater, together with an alkali material I such as sodlum hydroxide, sodium carbonate, ammonia, borax, or the like, to break up the binder material of the printers ink, and a quantity of bentonite, with an adeuate supply of water.- Bentonite in water forms a substantially permanent colloidal solution, and the alkaline .material employed of course passes into solution in the water so that there is formed what we term an alkaline solution of bentonite. The alkali acts to decompose or break up the ink by, reason of its action upon the grease or oily content of the ink, thus freeing the pigment of the ink which is taken up by the bentonite. After the pulp has been thoroughly agitated and stirred in the beater,'to the end that these actions may take place, the pulp isthen thoroughly washed, preferably in running water, which carries away the alkaline bentonite solution and with it the constitu-' ents of the ink. This washing is continued until the ink is thoroughly removed. In order to neutralize any alkaline condition that may remain in the paper pulp after the washing, it is then treated with any suitable alkali neutralizer, as an acid, such as sulphurlc acid (H 800, or an acid salt. This. also acts to brighten the color. If desired,

si zin'g material is then added and, if the paper is to be colored, a suitable dye, as well as alum, and whnthoroughly mixed the. pulp is then remade into paper in any su t- I,

able or usual manner.

; One specific formula which we have found to be highly efficient and satisfactory consists in using-approximately 300 pounds of bentonite, 200 pounds of sodium carbonate,

' V and 8,000 gallons of waterto the ton of old newspaper to be treated. Another specific formula which we have also found advan-'- tageous consists in using approximately 150 pounds of bentonite, 32 pounds of sodium carbonate, 20 pounds of lime, and 8,000 gallons of water-to the ton of old newspaper to be treated. The process.. may be carried out at ordinary temperatures, but the de sired result is more ex editiously efiected if the temperature of t e initial charge israised to a degree not to exceed 120 F. and

then applying the cold washing water.

While there are several varieties of bentonite which may be employed, we have" found the variety known as wilkinite to be highly efiicacious.

Bentonite is .to be distinguished "clays" such, for example, as fullers earth and kaolin, in that with'neither of these can .a permanent colloidal solution-be obtained, since the particles of. the clayfrapidly settle out from the solvent suchas water, whereas bentomte forms a" substantially permanent col-I;

loidal solution, probably due not only to the fact that it is a different substance but "also to its different ph sical. characteristics, the. particles of bentomte'bein extremely small, 0%;(according to H: iley) being less than .0015 milhmeters in diameter. I I Whatever the reasons may be, we have discovered that an; alkaline" solution of I beniv tonite'efi'ectively'andra idl [-deinksflthepa per stockso' as tofren erLt 'e processfcoma' mercially practicable, whereas,- so: -far as jwezi are informed, all "of the prior methods" protion of an alkali an i the presence of water, drainingofi' the water and thenwashing posed with this objectin view have been abandoned incommercial practice, either be- 'cause of their ineflicient action in deinking,

or the time and cost of the practice, or both.

What is claimed is 1. The process of deinking paper which Q consists in subjecting the paper to an alkaline solution of bentonite. a

2. The process ofdeinking paper which consists in decomposing the ink, treating the ence of water, and then draining oil? the water.

-5. The process consists in subjectin of deinking paper which paper pulp to the at:- a bentonite solution in the pulp. v I

T6. The method ofdeinking paper which consists in subjectin the paper to the action of an alkali an then-treating it with a bentonite solution.

. 7. The method of'deinkin'gpaper which consists in decomposing the ink and then.- treating the mass witha bentonite solution.

.8. The process of deinking' paper which then washing the pulp, and then adding an .consists in subjecting paper pulp to the ac- 'tion of an alkaline solution of bentoiute,

acidulous material to neutralize any remain- I ing alkalinity. j

,9. The process whichj consists in subjectin paper pulp to the action 'of a'n -alkaline so ution ofbentonite, than washing-thepulp, and *then neutralizing any remaining alka- .HAROLD REY-Brent IIJOHN A. SCHREIBER.

n have hereunto" subsc'ribed 'fojur-names. 

